Efficient construction of a chiral all-carbon quaternary center by asymmetric 1,4-addition and its application to total synthesis of (+)-bakuchiol

摘要

The conjugate addition of lithium divinylcuprate to (4S,2'E)-3-(6'-TBDPS-3'-methylhex-2'-enoyl)-4-phe-nyloxazolidin-2-one proceeded efficiently to create a chiral all-carbon quaternary center with a high dia-stereoselectivity (R:S = 95:5). The absolute configuration of the newly generated chiral center was confirmed by applying this methodology to the total synthesis of (+)-bakuchiol.